<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" >
        let arr =[1,2,3,4];
        let c = arr.reduce((a,b) => a+b,10);
        console.log(c)
    </script>
</head>
<body>

</body>
</html>